Party-line measured-service telephone system



Jan. 13, 1925. 1,522,737

T. G. MARTIN PARTY LINE MEASURED SERVICE TELEPHONE SYSTEM Filed N0 5 191 Gonnector B...

Master Switch I Illl I l Line Switch TALBOT G. MARTIN, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PARTY-LINE MEASURED-SERVICE TELEPHONE SYSTEM.

Application filed November 5, 1919. Serial m. ssagzo.

[0 all whom it may concern:

Be it known that I, TALBOT G. MARTIN, a citizen of the United States of America, and a resident of Chicago, Cook County, and State of Illinois, have invented certain new and useful Improvements in Party-Line Measured-Service Telephone Systems, of which the following is a specification.

My invention relates to measured service equipment in combination with telephone systems.

More particularly this invention relates to measured service equipment for use in combination with party line telephone systems.

Heretofore it has been proposed to have a series of meters assigned to a party line, there being provided one meter individual to each of the subscribers on the line. Associated with said meters it has been proposed to use a progressively movable switch for connecting the proper meter with the line whenever one of the party line subscribers make a call.

However, this is the first time, as far as applicant is aware, that means of the particular type hereinafter described has been used for associating a subscribers meter with his line at the time that he is calling. More particularly, this is the first time, for example that a marginal device has been utilized for the purpose of controlling the meters with regard to the line. One of the objects of this invention is to providesuch marginal controlling device.

Another object of my invention is to proide details of imrnovement tending to increase the efficiency and servicea'bility of a measured service telephone system of the above character. v

To accomplish the foregoing and other useful ends my invention consists of means hereinafter set forth and claimed.

In the accompanying drawing Fig. 1 is a diagrammatic representation of a party line, shown at the left, calling another line, shown at the right, through the medium of a nonnumerical line switch, a trunk circuit, a numerical switch, such as the first selector represented by the dotted square, and a connector switch.

Fig. 2 is a diagrammatic illustration of the application of the invention to a four party line.

It might be stated before beginning a detailed description of the means for carrying out the invention, that the non-numerical switch referred to in the drawing may be of the general type shown in United States Patent No. 1,304,369, granted May 20, 1.919, to A. J. Ray. Furthermore, the trunk arrangement is in substance the same as the trunk arrangement shown in the same patent between the line switches O and C Also the first selector may be of the type shown in Patent No. 1,130,784, granted March 9, 1915, to Bernard D. Willis, while the connector ma be of the type shown in Patent No. 1,308, 49, granted July 1, 1919, to Arthur Bessey Smith. It will be understood, of course, that the called line may be provided with a line switch such as the line switch G shown in the last mentioned patent above. In this connection it may be well to state that the line switch assigned to any subscribers line is provided with suitable multiples in the connector banks assigned to the particular group to which the calling subscriber belongs. It should be likewise understood that although I have shown only one trunk between the calling line switch and the selector, there are a plurality of such trunks, all of which are accessible to a group of line switches insteadof only one line switch as is shown in the drawings, as is well understood, the line switches being usually greater in number than the trunks. Therefore, it follows that each selector switch is multipled through the trunksof all of the line switches of a given group. Likewise the connector switches which have access to the called subscriber are several in number instead of just one as shown in the drawings, and each connector switch is Inultipled to the banksof a series of select-or switches instead of to one selector switch only as in the drawings. The master switch shown near the bottom of the drawing is of the type shown in Patent No. 1,304,369 and is for the purpose of controlling the group of line switches that have access to the trunks shown. The telephone is of the usual twowire automatic type such as shown in the said Patent No. 1,304,369.

The following brief statement may help to make the operation of -the invention more readily understood :W'hen the subscriber A makes a call to subscriber B, he does so in the usual way and when subscriber B answers the reversal of battery in the front bridge of the connector switch operates the meter at which is individual to the station A. However, if subscriber C makes a call the marginal relay 2 energizes as soon as the subscriber Cremoves his receiver, which relay-in turn energizes the relay 3 associated with the meters 4 and 5 controlled respeetively by the magnetsa and 0, switching the magnet 0 into circuit in place of the magnet on, with the result that when the called subscriber answers the meter 5 is operated instead of the meter 4. This difference is due to the fact that station C does not have the resistance in the line that station A has, as will be described hereinafter,

Referring more in detail to the circuits shown in the drawing, it will be seen that when a subscriber A removes his receiver from the hook the line circuit is closed at the springs 6 and 7. This circuit extends as follows:

Through the polarized relay 8, resistance 9, line conductor 10, line relay springs 11 and 12, and through the marginal relay 2 and the line relay 13 to battery. The other side of the line circuit is closed through the transmitter at the telephone and through the other side of the line to ground at the line switch.

The resistance of this circuit is such that the marginal relay 2 does not operate, whereas the line relay 13 does. The result is that a circuit is closed through the pull in winding 14 of the line switch with the result that the connection is extended to the trunk in the usual manner. When the circuit is extended to the trunk the line relay in the selector switch supplies holding ground back over the trunk release conductor 15 in the usual way which ground energizes the hold in winding 16 of the line switch, thereby holding the connection between the line switch and the trunk. From this point on the extension and completion of the connection is obtained-by the operation of the dial at the station A, as usual.

It will be seen that when the line switch extends the line to the trunk a circuit is closed through the meter magnet a in series with the trunk relay 17. The current in this circuit is not sufficiently strong to energize the meter magnet a to cause the meter to register. but it is strong enough to cause the relay 17 to attract its armature. The result is that a circuit is closed through the springs 18 and 19 for applying a guarding potential at the master switch bank to make the trunk busy. Assuming now that the called station is B, upon removing the receiver thereat a circuit is closed through the reversing relay 20 which causes a reversal of current in that section of the talking circuit to the left of the condensers 21. This reversal affects the differential relay 22 in the trunk. This relay 22 does not ene 1-- gize when connection is first extended to the trunk, due to the-fact that the current 1n the right hand winding opposes the current in the. left hand winding. However,

when the reversal above mentioned occurs the relay 22 energizes with suflicient power to close the contacts 23 and 24. The result is that the right hand winding of the trunk relay 22 is eliminated from the talking circuit by the closure of contact between sprlngs 23 and 24. A further result 'of the energization of relay 22 is the closure of contacts 25 and 26 which establishes a shunt around the left hand winding of relay 17. This increases-the flow of current in the circuit of the meter magnet a, which latter then operates to register the call on the meter 4.

.The reversal of current also causes the polarized relay 8 at the station A to energize shunting the resistance 9 thereby increasing the flow of current to the transmitter at the station A in order to insure more effective talking. It will be seen that the polarized relay 8 is shunted by a condenser so that the voice currents may avoid the impedance which would be encountered around through the circuit that includes the polarized relay.

If the call for station B had been made from the station C instead of from the station A, as described, reversal of the current by the called party would have operated the meter 5 instead of the meter 4. The difference in action is as follows: Due to the absence in the station C of the resistance, shown in station A shunted by the condenser 27, when the subscriber C removes his receiver not only is the line relay 13 of the line switch C operatively energized, but the marginal relay 2 is also energized with the result that a circuit is established, upon the closure of contacts 28 and 29, through switching relay 3. The result of the energizing of relay 3' is that the meter magnet 0 is substituted for the meter magnet a in connection with the conductor 30 that runs to the magnet 17 Otherwise the operation of the line switch is exactly the same as in the preceding case. The result of the substitution of the magnet c for the magnet a is that upon the reversal of the current the magnet c is the one that is operated instead of the magnet a.

It will be seen therefore that normally the magnet a is connected to the conductor 30, whereas when the subscriber C calls the magnet 0 is connected to the conductor 30.

It will he observed that associated with the switching relay 3 tlli we are a pair of contacts 31 and 32 which are controlled by the switching relay 3. Whenever this relay 3 energizes these contacts are closed and a locking circuit over the trunk release conductor 15 set u in parallel with the bridge cut oil winding 16 of theiline switch. The object in having this locking circuit is to enable the relay 3 to remain energized after the line switch has extended connection to the trunk. that after such connection is made to the trunk the line switch armature 33 opens the circuit between the springs 11 and 12 which cuts oil not only the line relay 13 but the marginal relay as well, the two being in series.

It will be seen that when the subscribers are through talking the calling subscriber upon hanging up his receiver will release the connection in the usual manner by opening the line circuit and thereby causing the line relay 34 in the connector switch to fall back. When a connection is broken the line switch is restored and therefore the circuits between the line switch and the trunk are broken with the result that all of themagnets associated with the line switch are deenergized thereby restoring the equipment .to normal.

Although I have illustrated my invention in connection with a two-party line, it is applicable just as well to a multi-party line. For example, I may have a line D, Fig. 2, with a number of telephones A, F, E and C, A and C corresponding to stations A and C. This line instead of extending through only two relays such as the relays 2 and 13 corresponding'to relays 2 and 13, Fig. 1, may extend through four relays, the only provision being that when the telephone A is removed from the switch hook the resistance on the line is so great that only the relay 13, Fig. 2, energizes. When the receiver at the telephone F is removed the relays 2 and 13' energize, Fig. 2. When the receiver at E is removed the relays ac, 2 and 13 energize, and when. the receiver at C is removed the relays y,

w, 2 and 13 energize. Associated with these relays y, w, 2 are the auxiliary relays 3', 35 and 36, 3 corresponding to relay 3, Fig. 1. The relay 3' it will be seen controls two meter magnets a and f, the meter magnet a/ being individual to the subscriber A, and the meter magnet f being individual to the subscriber F, etc. It will be seen therefore that with this arrangement I can have a series of telephones on a party line and yet assign to each subscriber a.meter individual to him, controlling the assignment of the various meters to the line through the medium of marginal devices.

What I claim as my invention is:

1. In a measured service telephone system, a party line, a plurality of telephone stations assigned thereto, a plurality of meters associated with said stations normally disconnected from said line, each station having one of said meters assigned individ- It will ,be understood 7 ually thereto, marginal means for rendering any particular meter operative when the correspondin particular station is used for making a cal and means for operating the connected meter by a reversal of current in the lind.

2. In a measured service telephone system, a party line with a plurahty of tele phone stations assigned thereto, a plurality of meters, one individual-to each telephone station, marginal means for. determining that when a subscriber calls from a particular station. only the meter assigned to that station shall be operated, a non-numerical progressively movable switch assigned to said line for extending connections from said line to another line automatically, and means controlled by the 'response of the called party for automatically operating the meter determined upon.

3. In a measured service telephone system a party llne, a plurality of telephone stations assigned thereto, a plurality of meters associated with said stations normally disconnected from said line, each station having one of said meters assigned individually thereto, marginal means for connecting any particular meter for operation when the correspondin particular station [3 used for making a cal said meter operated by reversal. of current when the called subscriber answers, and a non-numerical progressively movable switch assigned to said line for extending connections from said line to another line automatically.

4. In a measured service telephone system, a party line with a plurality of telephone stations assigned thereto, a plurality of meters, one individual to each telephone station, marginal means for determining that when a subscriber calls from a particular station only the meter assigned. to that station shall be operated and for determining that when any subscriber calls his particular meter will be operated, a non-numerical progressively movable switch assigned to said line for extending connections from said line to another line automatically, other means for completing a connection with a called telephone line, and

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means controlled after connection has been merical progressively movable switch assigned to said line for extending connections from said line to another line automatically, other means for completing a connection with a called telephone line, and means controlled after the connection has been extended to the called line for reversing'the current on the callin" line tocause the meter individual to the station calling to register the call.

6. In a measured service telephone system, a party line with a plurality of telephone stations assigned thereto, a plurality of meters, one individual to each telephone station, marginal means for determining that when a subscriber calls from a particular station only the meter assigned to that. station shall be operated and for determining that when any subscriber calls his particular meter will be operated, a non-numerical progressively movable switch assigned to said line for extending connections from said line to another line automatically, other means for completing a connection with a called telephone line, and means controlled after connection has been extended to the called line for reversing the current on the calling line to cause the meter determined upon by the marginal device to register the call.

7. In a measured service telephone system, a party line, a plurality of telephone stations assigned thereto, a plurality of meters associated with said stations normally disconnected from said line, each station having one of said meters assigned individually thereto, marginal means for connecting any particular meter with the line' when the corresponding particular station is used for making a call, a non-numerical progressively movable switch assigned to said line for extending connections; from said line to another line automatically, other means for completing a connection with a called telephone line, and means controlled after the connection has been extended to the called line for reversing the current on the calling line to cause the meter determined upon by the marginal device to register the call.

8. In a measured service telephone system, a two-party line, a meter at the exchange for each station on the line, one of said meters being normally connected for operation, a line relay individual to said line and adapted to be energized over the two sides of said line in series when the receiver is removed at either station, a marginal relay in series with said line relay, a resistance in the line circuit at one of the stations for preventing said marginal relay from operating when the line relay is operated, -means for substituting the normally disconnected meter for the normally connected meter when the marginal relay 'is 9. In a measured service telephone sys:.,

tem, a two-party line, a meter at the exchange for each station on the line, a line" relay individual to said line and adapted to be energized over the line when the receiver is removed at either station, a marginal relay in series with said line relay, a resistance in the line circuit at one of said stations for preventing said marginal relay from operating when the line relay is operated, means controlled by said marginal relay for determining which of said meters is to be operated to register each call, and a single means for causing said resistance to be short circuited during a conversation involving the associated station and for also effecting the operation of the connected meter.

10. In a measured service telephone system, a two-party line, a meter at the exchange for each station on the line, a line relay individual to said line and adapted to be energized over the line when the receiver is removed at either station, a marginal relay in series with said line relay, a resistance in the line circuit at one of said stations for preventing said marginal relay from operating when the line relay is operated, meanscontrolled by said marginal relay for determining which of said meters is to be operated to register each call, a relay at the station having said resistance for eliminating the said resistance from the talking circuit when the call originates at said station, and a single means for operating said relay and for controlling the operation of the connected meter.

11. In a measured service telephone sys tem, a two-party line, a meter at the exchange for each station on the line, a line relay individual to said line and adapted to be energized over the line when the receiver is removed at either station, a marginal relay in series with said line relay, a resistance in the line circuit at one of said stations for preventing said marginal relay from operating when the line relay is operated, means controlled by said marginal relay for determining which of said meters is to be operated to register each call, means for reversing the current flow in the line when each call is answered, means responsive to the current reversal for operating the proper meter as determined by said marginal relay, and a polar relay at the station having said resistance operative responsive to the current reversal for each call originating at such station to eliminate said resistance from the talking circuit.

Signed by me at Chicago, Cook County, Illinois, this 31st day of October, 19-19.

TALBOT G. MARTIN.

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